View the list of Sample Business Letters Apology for Not Crediting Payment Disclaimer: Be aware that some of these sample letters have legal, financial, or other implications. If you are not sure about the use of any letter, consult with an appropriate professional first. Apology for Not Crediting Payment Dear Thank you for your assistance in helping us to locate your payment of (date) which had not been credited to your account. Please accept our apology for this error and for the overdue notices we sent to you. We appreciate your patronage and are sorry for the inconvenience caused by this error.